A Review on Applications of Vitamin B12 as Therapeutic Carrier in Drug Delivery

In the last decade, Vitamin B12 (VB12) had been used as a carrier for the successful delivery of drugs. This article reviews the different applications of VB12 in drug delivery as an absorption enhancer, a targeting moiety to cancer cells, ability to increase trans-epidermal transport across the airway epithelium, to enhance immune adjuvant properties, and as a pH-responsive carrier for improved oral drug delivery of poorly permeable drug molecules. VB12 has a self-intestinal uptake pathway by which it can be transported to the systemic circulation. The role of the intrinsic factor in the absorption of VB12 is also discussed in-depth to learn about improving the absorption of drugs having poor permeability. Continued research and optimization of formulations based on nanoparticles modified or conjugated with an active moiety like VB12 are expected to lead to a much sought- after noninvasive delivery of peptide-based therapeutics. This review summarizes the research studies and applications of VB12 used for improving drug delivery of drug substances by oral route due to its intestinal uptake pathway. This review can be of interest to researchers studying drug delivery of peptide or protein-based therapeutics and drug molecules having poor oral bioavailability.